The present disclosure relates to semiconductor device fabrication and more particularly, to protection of the wafer edge during processing of the wafer.
Photolithography is a commonly used technique in the manufacture of semiconductor devices. The process uses patterns to define regions on a substrate. More specifically, with photolithography, a photoresist layer may be formed on a substrate, such as a silicon wafer, and then the resist layer is covered with a mask containing a pattern. The mask is exposed to radiation, such as ultraviolet light (UV), which is transmitted through transparent areas of the mask to cause a chemical reaction in corresponding regions of the photoresist. In other words, in the course of processing integrated circuits and the like in semiconductor devices, a standard sequence may involve putting down a layer of material, depositing a layer of photoresist on the layer of material, patterning the photoresist by projecting a pattern on it, and developing the resist to produce a pattern of open areas that expose the material, with the other areas of the material still covered by the resist.
In addition, other etching and cleaning techniques may be used to create integrated circuit dies. During certain etching processes the edge of the wafer may need protection in order to avoid the formation of edge related defects (e.g., blistering, cracks formed from incomplete patterns) and to increase yielding die from the wafer.